1. Field of the Invention
The present invention relates to a transmission gear part called an idler reverse gear (hereinafter referred to as an idler reverse gear), a method and a device for manufacturing the same.
2. Description of the Prior Art
An idler reverse gear of prior art was made by uniting a transmission gear part and a hub synchro with a spline teeth for a synchro, which were formed individually, namely the transmission gear and the hub synchro were combined by an electron beam welding or fitting means.
The spline teeth for synchro formed on an outer peripheral surface of the hub synchro was formed only out of an area of a sink part.
There are many problems that the above prior arts need two times parts in order to form a transmission gear part and a hub synchro for a synchro individually and many and large investments of equipments owing to a build up process.
Moreover, it is difficult to secure the strength and the accuracy on uniting the transmission gear part and the hub synchro. For example, there are problems such as a strain due to heat on an electron beam welding, a phase lag of a teeth form and a shortage of strength against a torsion torque on a fitting means.
It is able to form a one-piece product having a transmission gear part and a hub synchro by cutting. Although, the above described method is inefficient and causes a high cost.